Bead breaker mechanism

ABSTRACT

A lower bead breaker is interconnected with an upper bead breaker through a fluid motor that powers both bead breakers, the lower bead breaker being pivotally connected to the motor&#39;&#39;s piston rod, and the upper bead breaker being pivotally connected to the motor&#39;&#39;s housing. The lower bead breaker is mounted for limited vertically upward movement in an arcuate path by virtue of a control arm that is pivotally fixed to the machine&#39;&#39;s main frame at one end and that carries the lower bead breaker&#39;&#39;s pivotal motor connection at the other end, and the upper bead breaker is mounted for limited vertically downward movement in a straight line path by virtue of the upper bead breaker&#39;&#39;s pivotal motor connection being captured in a vertical slot defined in the machine&#39;&#39;s stationary main frame.

United States Patent [191 Curtis Apr. 30, 197$ Magnum Automotive Equipment, Inc., Cincinnati, Ohio Filed: Jan. 30, 1973 Appl. No.: 328,017

Assignee:

vs. C]. 1s7/1.2s, 157/124 Primary tggmir eF-Othell M. Simpson 7 A lower bead breaker is interconnected with an upper bead breaker through a fluid motor that powers both bead breakers, the lower bead breaker being pivotally connected to the motors piston rod, and the upper bead breaker being pivotally connected to the motors housing. The lower bead breaker is mounted for limited vertically upward movement in an arcuate path by virtue of a control arm that is pivotally fixed to the machines main frame at one end and that carries the lower bead breakers pivotal motor connection at the other end, and the upper bead breaker'is mounted for limited vertically downward movement in a straight line path by virtue of the upper bead breakers pivotal motor connection being captured in a vertical slot defined in the machines stationary main frame.

5 Claims, 6 Drawing Figures [51] Int. Cl. 1360c 25/06 [58] Field of Search; 157/1.1.7, 1.2, 1.24, 1.26, 157/128 [56] References Cited UNITED STATES PATENTS 3,556,192 l/l971 Strang et a1 157/128 2,873,795 2/1959 Kleparchuk l57/1.l7

IMF :4; /o7- J/ a: llllllll PATENTEIMR so 1914 SHEEI 2 (IF 3 1 BEAD BREAKER MECHANISM the tires beads must somehow be disposed over one of the wheels rims into the wheels well area so as to positively locate the tire on the wheel. In demounting the tire from the wheeel, the tires beads must be somehow removed-from the wheels well area over one of the wheels rims so that the tire is free of the wheel. Over the years, a number of different types of automatic tire changing machines have been developed which provide means to mechanically assist an operator in mounting a tire onto, and demounting a tire from, a wheel. Thus, the main objective of an automatic tire changer machine is to aid an operator in demounting a worn or un- 1 desirable pneumatic tire from a wheel, and to aid an operator in mounting a new pneumatic tire onto a wheel. Most such tire changing machines include the structural components generally described below.

Generally speaking, the major structural components I of an automatic tire changer machine include a horizontally disposed table on which the wheel is initially positioned, an automatically rotatable centerpost that extends up from the table through the center of the wheel, and a mount/demount tool that functions to lift an old tires beads over the rim off the wheel when the old tire is being demounted, and to seat a new tires beads over the rim onto the wheel when the new tire is being mounted. The mount/demount tool is interconnected with the centerpost, and is machanically rotated relative to the wheel through that interconnection, to aid an operator in performing the tire mounting and demounting functions. p

In mounting a tire on a wheel, the tire tool (the mounting head of which cooperates with the wheels rim and the tires bead to aid in locating the bead within the wheels well area) is cooperatively engaged with the centerpost. The tire tool extends outward from the centerpost in a radial fashion, the centerpost in effect providing a vertical axis about which the tire tool is rotated for a single revolution, as well as providing the drive means to work the tools mounting head around the bead to locate the bead over the wheel 5 rim. Of course, a suitable power unit must be drivingly connected with the centerpost so that same can be mechanically rotated about its vertical axis.

In demounting a tire from a wheel, the tire tool (the demounting head of which cooperates with the tires beads to aid in lifting the beads over the wheels rim so as to free the tire from the wheel) is also cooperatively engaged with the centerpost. The tire tool likewise extends outward from the centerpost in a radial fashion, the centerpost again providing the vertical rotational axis for the tire tool as the tools demounting head is worked around the bead to lift the head over the wheels rim and off the wheel. The same power unit is employedto rotate the centerpost whether the tools mounting head or demounting head is cooperatively engaged with the wheel.

In addition to the structural components previously mentioned, the more advanced automatic tire changer machines also make use of a lower bead breaker and an upper bead breaker. 'Ihese bead breakers are used only when demounting a tire from a wheel, i.e., are not used when mounting a' tire onto a wheel. As is generally known, pneumatic tires are provided with a substantial degree of air pressure inside, and that air pressure must be relieved prior to removing or demounting the tire from the wheel. Further, and particularly in the case of tubeless pneumatic tires, the tires upper and lower beads (as the tire lies horizontally on the machines table) are stuck to some extent, i.e., are sealed, against the wheels upper and lower rims, respectively. Thus, the tires beads must be broken away from the wheels rims prior to removing the tire from the wheel during the demounting operation. The tire tool is used to demount the tire from the wheel, as previously explained, subsequent to breaking of the tires beads from the wheels rims.

The upper and lower bead breakers are mechanically operated by a power unit to perform the breaking function, i.e., to break the tire s upper and lower beads from the wheels upper and lower rims. In the more advanced automatic tire changer machines the upper and lower bead breakers are in the nature of jaws which are initially positioned adjacent the tires upper and lower beads, respectively, and which are then caused to move toward one another relatively simultaneously so as to compress the beads toward one another (i.e., toward the center plane of the wheel and away from the rims of the wheel), thereby breaking the tires beads away from the wheels rims and totally depressurizing the tire.

However, there is one major problem in connection with bead breaker mechanisms of the prior art which the bead breaker mechanism of this invention overcomes. This problem is occasioned by the fact that the upper and lower bead breakers of the prior art employ a single power unit to drive the upper and lower bead breakers toward one another so as to break the tires upper and lower beads from the wheels upper and lower rims. This dual use of a single power unit leads to instability in the supporting structure of the bead breaker mechanism, and also leads to relatively complex supporting structure for that mechanism, e.g., see the bead breaker mechanism structures illustrated in U.S. Pat. Nos. 3,032,095 and 3,064,718.

It has been one objective of this invention to provide a novel support structure for a fluid motor type power unit that interconnects an upper bead breaker and a lower bead breaker on an automatic tire changer machine. I

It has been another objective of this invention to provide a novel support structure for a fluid motor type power unit that interconnects an automatic tire changer machines upper and lower bead breakers, that structure providing stability to the mechanism, and being relatively economical to manufacture.

In accord with these objectives, this invention provides a lower bead breaker interconnected with an upper bead breaker through a fluid motor that powers both bead breakers the lower bead breaker being pivotally connected to the motors piston rod, and the upper bead breaker being pivotally connected to the motors housing. The lower bead breaker is mounted for limited vertically upward movement in an arcuate path by virtue of a control arm that is pivotally fixed to the machines main frame at one end and that carries the lower bead breakers pivotal motor connection at the other end, and the upper bead breaker is mounted for limited vertically downward movement in a straight line path by virtue of the upper bead breakers pivotal motor connection being captured in a vertical slot defined in the machines main frame.

Other objectives and advantages of this invention will be more apparent from the following detailed description taken in conjunction with the drawings in which:

FIG. 1 is a partially broken away perspective view il lustrating an automatic tire changer machine that incorporates an improved bead breaker mechanism structured in accord with the principles of this invention;

FIG. 2 is a cross-sectional end view taken generally along line 2-2 of FIG. 1 but with the machines shroud removed;

,FIG. 3 is a partially broken away side view illustrating the upper and lower bead breakers in home or fully retracted position;

FIG. 4- is a partial side view similar to FIG. 3, but with a portion of the machine not shown, in which the upper and lower bead breakers are shown in an intermediate operating position;

FIG. 5 is a view similar to FIG. 4 showing the upper and lower bead breakers in away or fully extended position; and

FIG. 6 is a perpsective view illustrating the major structural elements of the travel limiter assembly.

General Structure of Automatic Tire Changer Machine The improved bead breaker mechanism 10, 11 of this invention is illustrated in its structural environment in the Figures. As shown in the Figures the improved bead breaker mechanism 10, 11 is structurally integrated with an automatic tire changer machine 12.

The automatic tire changer machine 12 includes a horizontally disposed table 13 adapted to receive a wheel 14 having a fully inflated pneumatic tire 15 mounted thereon, see FIGS. 1 and 3. The wheel 14 is held in fixed position on the table by a holddown cone 16, the hold-down cone being threadedly engaged with exteriorly threaded (as at 17) cylinder 18. The cylinder 18 is immobily mounted to the table 13 by collar 19.

The table 13 itself is supported on and fixed to the machine's main frame 20, see FIG. 2. The main frame 20 includes parallel and spaced apart side walls 21, 22 that are stationary and that terminate in and are fixed to flanged feet 23. The feet 23 extend the length of the machine 12 and are adapted to be bolted to a concrete floor in, e.g., a gasoline station, to provide stability for the machine during its operational cycle. A shroud 24 is fixed to the main frame 20 for enclosing the operational structure, e.g., power units, of the machine 12.

A centerpost 25 extends vertically upward from beneath the table 13 to a terminal point above the wheel 14. The rotatable centerpost 25 is coaxially and interiorly located relative to the fixed threaded cylinder 18. The outside diameter of the centerpost 25 is sized relative to the inside diameter of the threaded cylinder 18 so that the centerpost can easily rotate relative thereto in either the clockwise or counterclockwise direction.

The centerpost 25 is mounted to the machines main frame 20 at its lower end portion between opposed plates 26 that are welded between side walls 21, 22 of the frame, each of the plates mounting a bearing block 27 which receives the centerpost. Thus, the centerpost 25 is supported for rotation at spaced locations adjacent its lower end portion by means of the two bearing blocks 27, and is supported for rotation adjacent its upper end portion by virtue of passing through threaded cylinder 18. The centerpost 25 carries a pinion gear 28, the gear being located on the centerpost between the bearing blocks 27 and being drivingly connected with a first or centerpost power unit 29.

The first modular power unit 29 is fixed to the machines main frame plates 26 in driving relation with the centerposts pinion gear 28. The first and centerpost power unit 29 includes a straight rack 30, fluid motor 31, and a pair of shock absorbers 32, see FIG. 3. Note that the linear rack 30 is oriented transverse to the centerpost 25, i.e., the linear rack is adapted to reciprocate in a horizontal path and the centerpost is adapted to rotate about a vertical axis. The linear rack 30 is directly fixed to the fluid motorfs piston (not shown), the fluid motor being a pneumatic motor (although it may be a hydraulic motor, if desired) capable of being operated by high pressure air such as is commonly found in gasoline stations and the like. Rotation of the centerpost 25 is operator controlled through foot pedals 33. The power unit 29 for rotating the centerpost 25 is particularly disclosed in US Pat. application Ser. No.

328,016, entitled CENTERPOST DRIVE MECHA- NISM, invented by William G. Brosene, Jr. filed simultaneously herewith. I

The automatic tire changer machine 12 also includes upper 10 and lower 11 bead breakers, as mentioned. The upper 10 and lower 11 bead breakers are adapted to move toward one another in general travel paths 41, 42, respectively, that are substantially vertical relative to the horizontal plane of the wheel 14 as the wheel rests on the machines table 13; note, however, that the upper bead breakers general travel path 41 is straight whereas the lower bead breakers general travel path 42 is arcuate. Operation of the upper bead breaker 10 is accomplished by moving upper blade 43 downwardly against the tires upper side wall 44 adjacent the tires upper head 45 by a second or bead breaker power unit 46. Operation of the lower bead breaker 11 is accomplished by moving lower blade 47 upwardly against the tires lower side wall 48 adjacent the tires lower bead 49 by the power unit 46. The second power unit 46, in effect, both interconnects and powers the two bead breakers 10, 11. This downward motion of the upper bead breaker 10 and upward motion of the lower bead breaker 11 may occur substantially simultaneously and, in essence, serves to break or separate the tires upper 45 and lower 49 beads away from the upper 50 and lower 51 rims of the wheel 14 on which the tire 15 is mounted, compare FIGS. 3 and 5. This prepares the tire for subsequent demounting from the wheel by use of the tire tool (not shown).

As noted, when an operator desires to demount a tire from a wheel, the operator must make use of the bead breaker mechanism 10,1] of this invention prior to removing the tire from the wheel. That is, the tire s beads must be broken away from the wheels rims prior to completely removing or demounting the tire from the wheel. After the beads have been broken, the slotted body section of a tire tool (not shown) is engaged with the centerposts flatted portion 34 so that rotation of 1 the centerpost 25 is translated into rotation of the tire tool. After the tire tool (not shown) has been engaged with the centerpost 25, and after the tire tools demount head (not shown) has been operatively positioned between the tires bead and the wheels upper automatic tire changer 12 is illustrated in US. Pat. ap-

plication Ser. No. 328,010, entitled MOUNTING HEAD FOR A TIRE TOOL, invented by Donald D. Rainey, filed simultaneously herewith.

DETAILED STRUCTURE OF BEA D BREAKER MECHANISM Upper Bead Breaker The upper bead breaker is interconnected wit power column 55 through collar 57, the power column being directly and pivotally connected, as at 56, with the bead breakers power unit 46, see FIGS. 3-5. The power column 55 functions to draw the upper bead breaker 10 downwardly against the upper side wall 44 of the tire during breaking'of the tires upper bead 45 from the wheels upper rim 50 because it is directly connected to the power unit 46 as will be explained in detail below.

The cylindrical collar 57 that interconnects the upper bead breaker l0 and the cylindrical power column 55 at thetop of thepower column is part of the upper bead breaker, the collar having an inside diameter relative to the power columns outside diameter that allows it to be telescoped over and axially slidable relative to the power column. The slidability of the collar 57 (and, hence, the upper bead breaker 10') relative to the power column 55 provides structure that allows the machines operator to position the upper bead breakers blade 43 on the topside wall 44 of the tire 15 being demounted regardless of the tread width W of-the tire on the machines table 13. Further, the slidability of the collar 57 relative to the power column 55, in combination with the concentricity of the collar/power column structure, allows the upper bead breaker 10 to be swung outwardly out of the way when the tire/wheel is being lifted on or off the table 13, i.e., allows the upper bead breaker 10 to be swung into a plane transverse to the plane in which it is shown in all the Figures, so that it is off to the side of the table 13 where it does not impede locating the tire/wheel on, or removing the tire/- wheel from, the table. Handles 54, 58 are permanently fixed to the upper bead breaker 10 to aid the operator in lifting or-moving the upper bead breaker upwardly along the power column 55 as desired by the operator. The upper bead breaker mechanism 10, its structural elements and its function, is more particularly illustrated in US. Pat. Application Ser. No. 328,008, entitled UPPER BEAD BREAKER MECHANISM, in-

' vented by David W. Besuden and William G. Brosene,

Jr., filed simultaneously herewith.

A latch 59' is adapted to cooperate with the upper bead breaker 10 and the power column 55. The latch 59 serves to maintain the upper bead breaker 10 in its preset location on the power column when the upper bead breaker mechanism is in use, i.e.,when the tires upper bead 45 is being broken from the wheel s upper rim 50. The latch 59, and its structural elements and its function, is more particularly illustrated in US. Pat. application Ser. No. 328,015, entitled POWER COL- UMN LATCH, invented by David W. Besuden, filed simultaneously herewith.

The power unit 46 and power column are located between the side walls planes, see FIG. 2. The power column 55 is permanently fixed to a U-shaped bracket 60 at its bottom end, see FIGS. 2 and 3. The U-shaped brackets arms 61 are pivotally connected to a crossbar 62 fixed immobily to power unit 46, thereby pivotally connecting (on axis 56) the upper bead breaker 10 and power column 55 to the power unit 46. The power units crossbar 62 extends between the beyond the main frames stationary side walls 21, 22, and each end 63, 64 of the crossbar is captured in a vertical slot 63, 69, respectively, defined in each of the main frames side walls. This element combination provides substantial stability and structural rigidity to the bead breaker mechanism 10, 11. Thus, the upper bead breaker 10 is adapted for vertical movement in a straight line path as will be explained in detail below, and is provided with a substantially in-line power thrust or transfer from the power unit 46.

A U-shaped holder or cradle 65 is mounted to the main frame 20, the arms 66 of the cradle being fixed to side walls 21, 22 of the main frame, see FIG. 3. The cradle 65 functions as a support for the power column 55 when same is in the home or nonoperative attitude illustrated in FIG. 3, the power column falling clockwise about the pivot axis 56 into home or supporting contact with the cradles base 67 when not in operational rela tion with the tire 15 as shown in FIGS. 4 and 5. Thus, and by virtue of the pivotal connection 56 between the power column 55 and the power unit 46, the upper bead breaker 10 can be manually moved between a home or rest position where it is supported by cradle 65 as shown in FIG. 3, and an operating position where it is operatively engaged with the tire 15 and wheel 14 as shown in FIGS. 4 and 5.

Power Unit The second or bead breaker power unit 46 is in the form of a fluid motor that may be either pneumatically or hydraulically driven, although a pneumatic motor 71 is illustrated. The pneumatic motor 71 includes housing 72 (on which ear 73 is fixed at the bottom end) and an extensible piston rod 74 (on which ear 75 is fixed at its top or exposed end), see FIG. 3. The bottom ear 73 carries crossbar 62, thereby pivotally interconnecting the motors housing 72 with the power column 55 (and, hence, with the upper bead breaker 10) at the columns bottom end on axis 56. The top ear 75 carries crossbar 76 to which the lower bead breaker 1 1 is pivotally connected, as at axis 77, thereby pivotally interconnecting the motors piston rod 74 with the lower bead breaker. The piston rod 74 is interconnected with a piston head 70 interiorly of the housing 72, thereby dividing the housing into chambers 78, 79. Chamber 78 is connected to a high pressure air source (such as is found in gasoline stations and the like) through source line 81 as is described below. A check valve to atmosphere is provided for chamber 79, the check valve allowing outside air to be drawn into the chamber 79 but preventing air within chamber 79 from being exhausted to atmosphere. 7

Motor springs 85 are located on the outside of the main frame s side walls 21, 22, and are provided to continually bias or load the fluid motors housing 72 into the home position as illustrated in FIG. 3. Thus, motor springs 85 also continuously bias the upper bead breaker 10 towards the home or rest position since same is connected (as at 56) to the motors housing 72. Each of the springs 85 is attached at one end to a pin 86 mounted on a side wall 21, 22 of the main frame 20, and attached at the other end to that motor crossbar 62 which is pivotally connected with the power column 55, see FIG. 2. Note that the springs 85 are located exteriorly of the main frames side walls 21, 22, and that the power columns bracket arms 61 are located interiorly of the main frames side walls, thereby trapping each side wall between a spring and a frame arm so as to positively maintain the crossbar within the vertical slots 68, 69 defined in the frames side walls during operation of the machine 12.

The pneumatic circuit for control of the fluid motor 71 is controlled by means of a foot pedal 87 adjacent the base 23 of the machine, see FIGS. 1 and 3. The foot pedal is interconnected by rod 84 with a spring 88 loaded three-way valve 89. The valve 89 is interconnected with power chamber 78 of the pneumatic motor 71 at motor port 90 and through line 81. The three-way valve 89 is continually biased toward vent port 91 by tension spring 88, thereby continuously opening power chamber 78 of the fluid motor 71 to atmosphere through line 81 unless the foot pedal 87 is actuated by the machines operator. The three-way valve 89 is also connected with a high pressure air source (through source port 92) such as commonly is found in gasoline stations and the like. Thus, when power chamber 78 is supplied with high pressure air through three-way valve 89 upon actuation of the foot pedal 87, the piston head 70 moves upwardly in the housing 72 (air in static chamber 79 being exhausted to atmosphere through leakage around piston rod 74 since check valve 80 is pressure biased closed). By exhausting static chamber 79 air to atmosphere through the port in motor housing 72 through which the piston rod 74 extends, a dashpot type effect is obtained because the air is forced out a restricted orifice. This dashpot effect prevents sudden movement to i the upper 10 and/or lower 11 bead breaker, with the accompanying shock to the equipment, if either of the tires beads should suddenly break away from the wheels rims. Upon release of the foot pedal 87 by the operator, the spring 88 loaded valve returns to vent port 91 so that power chamber 78 of the fluid motor 71 is vented to atmosphere. When the motors power chamber 78 is vented to atmosphere, springs 85 function to retract the motors housing 72 upwardly relative to the slots 68, 69 as atmospheric air is introduced into chamber 79 through check valve 80, thereby returning the motor housing 72 (and the upper bead breaker 10) to the home position.

The upwardly moving piston head 70 forces the top cross-bar 76 upwardly (to which the lower bead breaker 11 is interconnected, as will be explained in detail below), thereby breaking the tires lower head 49 from the wheels lower rim 51. When the piston reaches its upper travel limit (due to structure associated with the lower bead breaker 10 as will be explained in further detail below), the fluid motors housing 72 moves downwardly against the spring 85 forces. This forces the bottom crossbar 62 downwardly along a restricted linear path defined by the vertical slots 68, 69 in the main frame's side walls 21, 22, thereby drawing-the power column 55 (and, hence, the upper bead breaker 10) downwardly so as to break the tires upper bead 45 from the wheels upper rim 50.

Lower Bead Breaker The lower bead breaker 11 includes the slightly curved blade 47 that defines a leading edge 96, and that is oriented to contact the bead 49 area of a tire s lower side wall 48 with its top face 97. The blade 47 is integral with an arm 98 at each end thereof, the arms 98 (and, therefore, the blade 47) being pivotally connected to the power units top crossbar 76 at elbows 99, i.e., on pivot axis 77.

The lower bead breakers blade 47 is spring 101 loaded. This spring loading continually biases blade 47 to move about axis 77 toward the table 13, i.e., in a counterclockwise direction as illustrated in the Figures and continually biases blade 47 toward the rest or home position where piston rod 74 is fully retracted into motor housing 72, see FIGS. 2 and 3. The detailed effect of the springs 101 is described in detail below. Each spring 101 is connected at one end to a pin 102 fixed on the lower bead breakers arm 98 adjacent the arm s foot 103, and is connected at the other end to pin 104 fixed on the main frames side wall 21, 22 adjacent the base 23 of the main frame. A step 108 is fixed to the outside of each of the main frames sidewalls 21, 22, the steps being positioned to cooperate with the cam toes 109 of the lower bead breakers arms 98 as will be described in detail below. The lower bead breakers arms 98 are positioned exteriorly of the frames side walls 21, 22, and the springs 101 are located on the outside of the frames side walls, thereby capturing the side walls of the main frame between the lower bead breakers arms so as to prevent peripheral movement'of the lower bead breaker mechanism 11 relative to the table 13.

Control arms 105 are connected with the lower bead breakers blade 47 and pneumatic motor 71 to guide or control the upward arcuate general path 42 of the blade when the motor is energized. A control arm 105 is mounted on each side of the machines main frame 20 exteriorly of the frames side walls 21, 22, see FIGS. 2 and 3. Each control arm 105 is pivotally mounted to a side wall 21 or 22 at one end by pin 106 to provide pivot axis 107, and is also pivotally connected to the motors upper'crossbar 76 at the other end on pivot axis 77. These control arms 105 (both of which have a common pivot axis 107 where they are connected to the main frames side walls 21, 22) function to allow the pivotal interconnection of the lower bead breakers blade 47 with the fluid motors crossbar 76 to track in an upward arcuate path 42, thereby providing a simple means during use to stabilize the pivot axis 77 of the lower bead breakers blade as the blade is being moved upwardly by the motor 71 and as the blade is pivoting on the upper crossbar 76.

The lower bead breaker 11 also includes a travel limiter assembly 112 that functions to limit the upward travel of the lower bead breakers blade 47, see FIGS. 3 and 6. Such limitation on the upward movement of the lower bead breakers blade 47 is desirable if a narrow tread width W tire is being processed on the machine. The travel limiter assembly 112 includes a pair of travel limiter arms 113, each being pivotally mounted to the inside of the main frames side walls 21,

22, respectively, on pivot axis 114 by pin 115. Each travel limiter arm 113 is notched at the upper end to define'a seat 1 16, this seat being adapted to function as an abutment for bar 117 fixed to and extending between the control arms 105.

The travel limiter arms 113 arespring 118 loaded continuously to that attitude illustrated in FIG. 3, and are connected with that spring 1 18 by means of a positioner arm 119 which extends from beneaththe table 13 beyond the machines shroud 24. The positioner arm 119 is carried by the main frames side walls 21, 22, pivot end 123 of the arm 119 protruding only slightly through hole 120 in side wall 22 and extending a substantial distance beyond side wall 21 after passing through elongated slot 121 so that handle end 122 protrudes outward from beneath the table 13 where it is readily accessibleto the operator. The spring 118 is located exteriorly of the side wall 21, and is fixed at one to the positioner arm 119 and at the other end to a hole 124 in the frames side wall 21. Cotter pin125 is passed through the arms pivot end 123 exteriorly of the side wall 22. Thus, the control arm 119 is adapted to pivot about general pivot axis 126 in a horizontal plane, the limits of that pivotal movement being defined by the ends 127, 128 of the elongated slot 121. The positioner arm 119 is connected to frame member 129 (and,

- hence, to the travel limiter arms 113 since those arms 113 are connected by theframe member 129) by link 130, see FIG. 6.

tires upper side wall 44, and the power column 55 is pivoted about axis 56 to its rest position against the base 67 of cradle 65. Further, the lower bead breaker 11 is retracted away from the table 13 and out of contact with the tires lower side wall 48. The power chamber 78 of the fluid motor 71 is vented to atmosphere through vent port 91 in the three-way valve 89, and static chamber 79 is vented to atmosphere through the port where piston rod 74 protrudes from motor housing 72. Thus, pressure in both chambers 78, 79 of the pneumatic motor 71 is atmospheric. This motor 71 condition allows springs 85 to fully retract the motors housing 72 and cross-bar 62 up to the top end 136 of the vertical slots 68 in'the main frames side walls 21, 22, thereby pushing the power column 55 (and, hence, the upper bead breaker 10) up into the home position shown in FIG. 3. This motor 71 condition also allows springs 101 to fully retract the piston rod 74 into the motor housing 72, thereby retracting the lower bead breaker s blade 47 along arcuate path 42 into the home position. The lower bead breakers blade 47 is fully retracted out of contact with the table 13, as the piston rod 74 is drawn into the housing 72 by the springs 101, by virtue of cam toes 109 on the blade s arm 98 which ride up on stop blocks 108 fixed to the machines side walls 21, 22 as the piston rod 74 bottoms out-into the motors housing 72. This causes the lower bead breakers blade 47 to pivot away from the centerpost 25 matically positions the travel limiter arms 116 in location for use with a narrow tread width W tire, i.e., in location as shown in'FIG. 3. When the travel limiter arm is in this operational-attitude, and as the lower bead breakers blade 47 is moved upwardly by the fluid motor 71, bar 117 (which connects the lower bead breakers arms 98) tracks or rides on edges 131 of the travellimiter arms 113. Thus, the interengagement of the lower bead breakers bar 117 with the travel limiter arms seats 116 is assured so as to limit the upward travel movement of the lower bead breakers blade 47.

When the positioner arm 119 is drawn to the left (as viewed in FIGS. 3 and 6) by manually grasping the arms handle end 122, the link 1130 pivots the travel limiter arms 113 counterclockwise (as viewed in the figures) about pivot axis 114 so as to remove seats 116 from the travel pathof the bar 1 17 that joins the lower bead breakers arms 98, thereby allowing the lower bead breakers blade 47 to continue in its upward travel until edges 133 of the lower bead breakers control arms 105 engage the underside or base rim 132 of the table 13. The handle end 122 of the positioner arm 119 must be manually held against slot end 128'when the extra upward travel of the lower bead breakers blade 47 is desired; once the handle end is released the positioner arm returns to the FIG. 3 attitude because of its spring 118 loading.

DETAILED OPERATION OF BEAD BREAKE MECHANISM (clockwise as shown in the Figures) against the bias of springs 101. The travel limiter assembly 112, unless manually withdrawn from position with the lower bead breakers bar 117, is spring 118 loaded into that position so that edges 131 of the travel limiter arms 113 are urged against the lower bead breakers bar 117.

Prior to commencing operation of the bead breaker mechanism 10, '11, the upper bead breakers blade 43 is positioned in relation to the tires top side wall 44 and the wheels top rim 50 as illustrated in FIG. 4 by manually pivoting power column 55 about axis 56, thereby pivoting same toward the centerpost 25 and off the base 67 of cradle 65. A more particular descriptionof the upper bead breaker 10, and its operation, as mentioned prior hereto will be found in U.S. Pat. application Ser. No. 328,008, entitled UPPER BEAD BREAKER MECHANISM, invented by William G. Brosene, Jr. and David W. Besuden, filed simultaneously herewith. Power column latch 59 associated with the upper bead breaker 10 maintains the upper bead breaker in fixed position on the power column 55 during operation of the bead breaker mechanisms 10, 1 1, the structure and operation of the latch being more particularly set out in U.S. Patent Application Ser. No. 328,015, entitled POWER COLUMN LATCH, invented by David W. Besuden, filed simultaneously herewith.

- After the upper bead breaker 20 has been operationally located as illustrated in FIG. 4, the operator depresses foot pedal 87, thereby causing the bead.45, 49 breaking operational sequence to be carried out automatically until both beads are broken away from the wheel s rims 50, 51 as illustrated in FIG. 5. When the foot control pedal 87 of the pneumatic circuit is depressed, three-way valve 89 is biased to the high pressure air port 92. This introduces high pressure air into the fluid motors power chamber 78 through line 81, thereby forcing the piston toward the top of the motor housing 72 from the bottom of that housing. As

the piston 70 is forced toward the top of the motors housing 72, the lower bead breakers blade 47 is moved upwardly along arcuate path 42 (since it is connected to piston rod74 through crossbar 76), see FIG. 4. As the lower bead breakers blade 47 is moved upwardly, the lower bead breakers feet 103 are lifted of the stationary stop blocks 108, thereby allowing the lower bead breakers blade to pivot about axis 77 toward the centerpost 25, i.e., in a counterclockwise direction as illustrated in the Figures. It is important to note, that once the lower bead breakers feet 103 are removed from interengagement with the stop blocks 108, the leading edge 96 of the lower bead breakers blade contacts the table 13 and rides up on the tables surface until it hits the wheels lower rim 51. As the pneumatic motor 71 continues to move the lower bead breakers blade upwardly, the blade rides up on the wheels rim 51 and tracks or follows the rims contour until the tires lower bead 49 is displaced into the wheels well 138, see FIG. 5. This tracking function of the lower bead breakers blade 47 is a result of the spring 101 loading provided, that spring loading tending to rotate the lower bead breakers blade in the counterclockwise direction as illustrated in the Figures.

As the lower bead breakers blade 47 moves upward in response to the fluid motor 71', bar 117 fixed between the lower bead breakers arms 98 tracks along edge 131 of the travel limiter arms 113 when the travel limiter assembly 112 is in the attitude illustrated in FIGS. 3-5. The lower bead breakers bar 117 utilimately abuts against or is caught by seats 116 defined in the travel limiter arms 113 at the top thereof. Thus, the upward travel of the lower bead breakers blade 47 is limited by this interengagement of the lower bead breakers bar 117 with the seats 116 defined by the travel limiter assemblys arms 113.

The travel limiter assembly 112 is functionally interposed to cooperate with the lower bead breakers bar 117 only when a relatively narrow tread width W tire l5 is in place on the machines table 13. A relatively wide tread width tire requires additional upward travel of the lower bead breakers blade 47 so as to ade quately break the tires lower bead away from the wheels lower rim. When such is desired, the handle end 122 of positioner arm 119 is grasped by the operator and the positioner arm pivoted about axis 126 against the bias of spring 118, thereby removing the travel limiter arms 113 from the travel path of the lower bead breakers bar 117. The positioner arm 119 is then manually held against slot end 128 against the spring 118 bias while the lower bead breaker is operated; this out-of-the-way or nonfunctional attitude of the travel limiter assembly is illustrated in phantom lines in FIG. 5. When the travel limiter assembly 112 is out of operational position as shown in FIG. 5s phantom lines, the upward movement of the lower bead breakers blade 47 is limited by contact of the control arms 105 with the underside of the machines table 13, i.e., with the table's base rim 132.

Once the lower bead breaker 11 has topped out, i.e., once the lower bead breaker has either abutted against the seats 116 defined by the travel limiter arms 113 (if those arms are in operational position) or once the control arms 105 have abutted the table's base rim 132 (if the travel limiterassembly 112 has been retracted by use of the positioner arm 119), the pneumatic motor's housing 72 begins to move downwardly in response to the continued pneumatic pressure in power chamber 78. This downward motion of the motors housing 72 is occasioned because of the fact that the motors piston head 70 is now in a fixed'location and unable to move upward any further (either because lower bead breakers bar 117 is interengaged with the travel limiter arms seats 116 or because the control arms 105 are abutted against the bottom edge 132 of the machines table 13). This for the reason that the high pressure air in the fluid motors power chamber 78 provides downward force on the bottom of the motors housing 72 sufiicient to overcome the spring 85 loading in the upward direction. The downward motion of the fluid motors housing 72 is, of course, translated into downward motion for the power column 55 and upper bead breaker mechanism 10 because the power column is directly connected with the housing by crossbar 62 at pivot axis 56. The downward motion of the fluid motors housing 72 is vertical in nature because of the vertical slots 68, 69 in the main frames side walls 21, 22, thereby guiding the upper bead breaker 10 downward in a vertical, straight line path. The downward movement of the fluid motors housing 72 is terminated when crossbar 62 bottoms out against the bottom end 137 of the vertical slots 68, 69. At this location the motors piston rod 74 and housing 72 are fully extended relative one to the other, and the tires upper bead 45 has been broken away from the wheels top rim 50 as well as the tires lower bead 49 has been broken away from the wheels bottom rim 51, see FIG. 5.

After the tire's beads 45, 49 have been broken away from the wheels rims 50, 51, the operator releases foot pedal 87. The spring 88 loading on the three-way valve 89 returns the valve to the vent port 91 attitude, thereby releasing the high pressure air from the power chamber 78 in the fluid motor 71. Once the motors high pressure chamber 78 is exhausted to atmosphere, springs cause the housing to move upwardly until crossbar 62 abuts top slot ends 136 of the main frames vertical slots 68, 69, i.e., springs 85 cause the motors housing 72 to return to the home position illustrated in FIG. 3. This return of the fluid motors housing to the attitude illustrated in FIG. 3 causes the power column 55 to move upwardly and, thereby, causes the upper bead breaker 10 to be returned to the initial or starting position illustrated in FIG. 3 from whence it can be moved out of operational contact with the tire 15. Further, the piston rod 74 is fully retracted into the fluid motor's housing 72 and the lower bead breaker ll drawn downwardly because of springs 101 fixed at one end to the machines main frame 20 and at the other end to the lower bead breaker arms 98. As the lower bead breakers blade 47 is drawn downwardly by springs 101, same follows the contour of the wheels outer surface and of the table in a reverse direction until feet 103 of the lower bead breakers arms approach the stop blocks 108. As cam toes 109 engage the stop blocks 108, the lower bead breakers blade 47 is pivoted clockwise as illustrated in the figures so as to remove same from contact with the machines table 13 back into the home or fully retracted attitude illustrated in FIG. 3.

The operation of the bead breaker mechanism 10, 11 of this invention has been described by indicating that the lower bead breaker 11 is first pushed upwardly, and the upper bead breaker 10 is subsequently pulled downwardly, by the fluid motor 71. Actual operation of the bead breaker mechanism 10, 11 may or may not follow thisexact sequence. In actual operation it may be the upper bead breaker' that will move downwardly prior to the lower bead breaker 11 moving upwardly. However, and as is most often the case, actual operation of the machine will result in both upper 10 and lower 11 bead breakers moving toward one another in a substantially simultaneous manner. The exact sequence of bead breaker mechanism 10, ll operation is mainly dependent on the degree to which each of the tires beads 45, 49 are stuck or adhered to the wheels rims 50, 51. For example, if the tire's upper bead 45'is more tightly stuck or adhered to the wheels upper rim 50 than is the tires lower bead 49 stuck or adhered to the wheels lower rim 51, then the lower bead breaker 11' will moveupwardly before the upper bead breaker 10 moves downwardly because there will be less initial resistance for the lower bead breaker to overcome than there is resistance for the upper bead breaker mechanism to overcome. However, in actual operation it will more likely be the case that the upper 10 and lower 11 bead breakers will operate substantially simultaneously upon introduction of high pressure air to the power chamber 78 of the pneumatic motor 71 once the pedal 87 has been depressed by the operator because it is most often the case that both of the tire s beads 45, 49 are roughly stuck to the same degree to the wheels rims 50, 51.

1 Having described in detail the preferred embodiment of my invention, what I desire to claim and protect by Letters Patent is:

1. An improved bead breaker mechanism for an automatic tire changer machine, said bead breaker mechanism comprising a fluid motor, said'fluid motor including a piston rod and a housing,

a power column pivotally connected at the bottom end to one of Said motors piston rod and housing,

said power column mounting an upper bead breaker at the top end thereof, and a stationary frame structure that defines a slot therein, the pivotal connection of said power column with said fluid motor being captured in said slot, said pivotal connection being movable from one end of said slot to the other in response to operation of said fluid motor, and said slot defining start and stop limits on the movement of said upper bead breaker when breaking a tires bead from a wheel's rim on said machine.

2. An improved bead breaker mechanism as set forth in claim 1 including motor spring means connected with said fluid motor,

said spring means being adapted to bias continuously said fluid motor to home position relative to said slot. 1

3. An improved bead breaker mechanism as set forth in claim 2 wherein said slot is substantially vertical so as to provide an in-line thrust transfer from said fluid motor to said upper bead breaker.

4. An improved bead breaker mechanism as set forth in claim 2 including valve means interposed between said motor and a high pressure fluid source, said valve means being spring loaded to vent and being operable by a foot pedal.

5. An improved bead breaker mechanism as set forth in claim 3 wherein said frame includes opposed stationary side walls, said opposed side walls each having a vertical slot therein such that said slots are located opposite one another, and wherein said pivotal connection of said power column and fluid motor includes a crossbar fixed to one of said fluid motors piston rod and housing, said crossbar being captured within and extending between said vertical slots, and said power column being pivotally connected to said crossbar.

. '-UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 7 Dated April 30, 1974 Inventor(s) John T. Curtis It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 4, Line 16 after the word first, "and" should be -or-.

Column 4, Line 46 "head" should be -bead-.

Column 6, Line 15 after the word between "the" should be -and--.

Column 6} Line 17 after the word slot "63" should be -68-.

Column-1 0,Line '56 after the word breaker "20" should be --l0.

Column ll L'ine 30 after the numeral 117 "utilimately" should be -ultimately.

Claim 1 Column 14 Line 6 please delete [from] Line 7 please delete [one end of] and insert --along-; Line 7 please delete [to the other] Signed and sealed this 17th day of September 1974.

(SEAL)- ----A-t-tos McCOY M. GIBSON JR. C. MARSHALL DANN Attesting Officer Commissioner of Patents FORM PO-1OSO (10-69) USCOMM-DC 60376-P69 9 TS. GOVERNMENT PRINTING OFFICE: I989 0J66-JJ4 

1. An improved bead breaker mechanism for an automatic tire changer machine, said bead breaker mechanism comprising a fluid motor, said fluid motor including a piston rod and a housing, a power column pivotally connected at the bottom end to one of said motor''s piston rod and housing, said power column mounting an upper bead breaker at the top end thereof, and a stationary frame structure that defines a slot therein, the pivotal connection of said power column with said fluid motor being captured in said slot, said pivotal connection being movable from one end of said slot to the other in response to operation of said fluid motor, and said slot defining start and stop limits on the movement of said upper bead breaker when breaking a tire''s bead from a wheel''s rim on said machine.
 2. An improved bead breaker mechanism as set forth in claim 1 including motor spring means connected with said fluid motor, said spring means being adapted to bias continuously said fluid motor to home position relative to said slot.
 3. An improved bead breaker mechanism as set forth in claim 2 wherein said slot is substantially vertical so as to provide an in-line thrust transfer from said fluid motor to said upper bead breaker.
 4. An improved bead breaker mechanism as set forth in claim 2 including valve means interposed between said motor and a high pressure fluid source, said valve means being spring loaded to vent and being operable by a foot pedal.
 5. An improved bead breaker mechanism as set forth in claim 3 wherein said frame includes opposed stationary side walls, said opposed side walls each having a vertical slot therein such that said slots are located opposite one another, and wherein said pivotal connection of said power column and fluid motor includes a crossbar fixed to one of said fluid motor''s piston rod and housing, said crossbar being captured within and extending between said vertical slots, and said power column being pivotally connected to said crossbar. 